1. Field of the Invention
The invention relates to a novel process for the production of aromatic polyesters utilizing mixed anhydrides as intermediates, and to certain novel aromatic polyesters produced thereby.
2. Description of Related Art
The following information is disclosed in accordance with the terms of 37 CFR 1.56, 1.97 and 1.98.
J. E. McIntyre et al., Polymer: 30 (April 1989), 732-738, disclose polyesters of 4,4,'-hexamethylenedioxy-bis-benzoic acid and chlorohydroquinone.
U.S. Pat. No. 4,296,232 issued Oct. 20, 1981 to Maresca et al. discloses the preparation of polyarylates, i.e., aromatic polyesters, by reacting a diester of a dihydric phenol, e.g., bisphenol A, with an aromatic dicarboxylic acid, in the presence of a diphenyl ether compound and a magnesium catalyst.
A. Fradet et al., Makromal. Chem. 88, 1233-1251 (1987) disclose thermotropic polyesters of terephthalic acid and 4,4,'-alkylenediphenols.
Belgian Patent No. 549,667, published Nov. 16, 1956, C.A. 52:5033 g (1958) disCloses a process for the preparation of polyethylene terphathalate (PET) comprising the steps of forming a mixed anhydride of terephthalic and acetic acids, heating the latter mixed anhydride as a solution in 1-methylnaphthalene to distill off acetic acid and acetic anhydride and obtain a polymeric mixed anhydride containing 96% of terephthalic moieties, and reacting the latter polymeric anhydride with ethylene glycol in the presence of antimony trioxide to obtain PET.
K. W. Leong et al., "Synthesis of Polyanhydrides: Melt-Polycondensation, Dehydrochlorination and Dehydrative Coupling" published in Macromolecules, 20(4), 705-712, (April, 1987), disclose a variety of polyanhydrides including copolyanhydrides of bis(carboxyphenoxy)alkanes with sebacic acid.
K. W. Leong et al., "Polyanhydrides for Controlled Release of Bioactive Agents," published in Biomaterials 1986, Vol. 7, September, 364-371, disclose the use of various polyanhydrides including copolyanhydrides of bis(carboxyphenoxy)alkanes with sebacic acid, as controlled release agents for drugs in the form of polymer matrices containing the drug.
Pending application Ser. No. 370,929 filed June 23, 1989 by Gupta et al., discloses and claims a process for producing aromatic polyesters comprising forming a mixed anhydride of isophthalic and/or terephthalic acid with acetic acid and subsequently reacting the mixed anhydride with bisphenol A.